Intervertebral implants

ABSTRACT

An interbody implant can comprise a cage and a porous structure. The cage can comprise an anterior segment, a medial segment, a posterior segment and a lateral segment contiguously connected to each other to define an interior space. The porous structure can be located in the interior space and can be bounded by the cage. The porous structure can comprise opposed superior and inferior surfaces exposed through the cage, an internal cavity located in an interior of the porous structure, and a plurality of ports connecting the internal cavity to the superior and inferior surfaces. A superior-inferior stiffness of the interbody implant can be defined by the porous structure. The porous structure can be compressed within a patient by movement of the spine to biologically stimulate bone growth in vertebrae adjacent the interbody implant. The implant can be configured for lateral, anterior and posterior insertion at different spine levels.

CLAIM OF PRIORITY

This application claims the benefit of U.S. Provisional PatentApplication Ser. No. 62/778,543, filed on Dec. 12, 2018, and claims thebenefit of U.S. Provisional Patent Application Ser. No. 62/830,863,filed on Apr. 8, 2019, the benefit of priority of each of which isclaimed hereby, and each of which is incorporated by reference herein inits entirety.

TECHNICAL FIELD

This document pertains generally, but not by way of limitation, toimplants for positioning between adjacent bones, such as can be used inspinal correction procedures. More specifically, but not by way oflimitation, the present application relates to implants having improvedosseointegration.

BACKGROUND

A spinal column can require correction of spinal deformities andabnormalities resulting from trauma or degenerative issues. Variousmethods of correcting issues with the spinal column can include fusingadjacent vertebrae together with a spacer and/or a rod system toimmobilize the degenerated portion of the spine. Such procedures can bebeneficial in patients having diseased or degenerated disc materialbetween the vertebrae. For example, intervertebral implants can bepositioned between adjacent vertebrae to fuse the vertebrae together,after disk material located therebetween is removed. In order tofacilitate fusion of the adjacent vertebrae, the implants can includevarious cavities and porous surfaces that promote growth of bonematerial into the implant. However, inclusion of such cavities andporous features can complicate construction of the implant and result inimplants that are not as strong as is desirable for placement betweenadjacent vertebrae.

Examples of intervertebral spacer implants are described in U.S. Pat.No. 8,454,700 to Lemoine et al.; U.S. Pat. No. 9,662,226 to Wickham; andU.S. Pub. No. 2017/0333205 to Joly et al.

OVERVIEW

The present inventors have recognized, among other things, that aproblem to be solved can include the difficulty of providingintervertebral implants that simultaneously provide bone support to theadjacent bones, facilitate in-growth of bone to enhance stability, thatare easy to implant, and that better approximate the elastic modulus ofnatural bone. For example, it can be desirable to provide interbodyimplants that are porous to facilitate bone in-growth, but that are nottoo rigid such that they cannot compress under loading. Stiff implantscan be both uncomfortable for the patient and can inhibit boneyin-growth, as discussed below. Additionally, porous bodies can sometimesbe difficult to implant between adjacent vertebrae due to the porousmaterial catching on anatomy while being slid between the vertebrae.

Furthermore, the present inventors have recognized that intervertebralimplants that are overly stiff in the superior-inferior direction caninhibit boney in-growth. For example, a rigid implant can be interpretedby the human body as being sufficiently strong if no compression occursin the implant from adjacent vertebrae during movement of the spinalcolumn. As such, the human body will not be induced into biologicallypromoting bone growth in that area. However, if the intervertebralimplant is permitted to compress under loading from adjacent vertebraeduring movement of the spinal column, the human body can interpret suchcompression as a need for strengthening the bones in that area and cantherefore react by biologically promoting bone growth in those bones,which can subsequently extend into pores and cavities of an adjacentimplant. The ideal intervertebral implant would perfectly mimic naturalbone in order to enhance the natural healing reaction of surroundingtissues.

The present subject matter can help provide a solution to theseproblems, such as by providing an interbody implant that is porous toaccept boney in-growth, while also not being overly stiff in thesuperior-inferior direction. The interbody implant can have a porousstructure that has a stiffness (e.g., modulus of elasticity) thatreplicates stiffness of natural bone. The interbody implant canadditionally be strengthened in other dimensions, such as in thetransverse plane, to increase stability of the device and facilitateinsertion into the anatomy. In particular, an interbody implant can havea porous structure being made of a material that has a stiffness thatpermits superior-inferior compression, but that is wrapped or partiallysurrounded along anterior, posterior and medial-lateral surfaces by asolid cage-like or cerclage structure to provide strength to the porousstructure. The cage-like or cerclage structure can be smooth and shapedto facilitate insertion between vertebrae.

In an example, an interbody implant can comprise a first cage comprisingan anterior segment, a medial segment, a posterior segment and a lateralsegment contiguously connected to each other to define an interiorspace, and a porous structure located in the interior space and boundedby the cage and that can comprise opposed superior and inferior surfacesexposed through the first cage, an internal cavity located in aninterior of the porous structure, and a plurality of ports connectingthe internal cavity to the superior and inferior surfaces.

In another example, a method of implanting an interbody implant betweenadjacent bones to promote bone in-growth can comprise inserting theinterbody implant between adjacent bones, the interbody implant cancomprise a porous structure comprising a monolithic body formed of aporous material replicating porosity of human bone, an interior cavity,and a plurality of openings in the monolithic body extending from theinterior cavity to an exterior of the monolithic body, and a cagestructure circumscribing a portion of the monolithic body in atransverse plane, positioning the plurality of openings against surfacesof the bones to allow for in-growth, and permitting the porous structureto compress in a superior-inferior direction between the bones andwithin the cage structure to stimulate biological bone growth within thebones.

In an additional example, an intervertebral implant for lateralinsertion can comprise a porous structure formed of a porous materialthat can be shaped to define an interior cavity and a plurality oflongitudinal passages extending through the porous structure tointersect the internal cavity, a first cerclage cage horizontallysurrounding the porous structure, and a second cerclage cagehorizontally surrounding the porous structure uncoupled from the firstcerclage cage such that a longitudinal stiffness of the intervertebralimplant is defined by the porous structure.

While depicted in certain examples as being separate structures, thecage-like solid structures and the porous inner structure can be formedas a unitary structure, such as through additive manufacturingtechniques including 3D printing using selective laser sintering, amongothers. Accordingly, despite being discussed and illustrated as separatestructures, in certain examples the entire intervertebral implant can be3D printed as a single structure with varying degrees of porosity.

This overview is intended to provide an overview of subject matter ofthe present patent application. It is not intended to provide anexclusive or exhaustive explanation of the invention. The detaileddescription is included to provide further information about the presentpatent application.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of an interbody implant of thepresent application showing the porous structure positioned betweensuperior and inferior cages.

FIG. 2 is a perspective view of a posterior side of an interbody implantof FIG. 1 comprising a cage structure surrounding a porous structure.

FIG. 3 is a perspective view of an anterior side of the interbodyimplant of FIGS. 1 and 2 showing an opening into an internal cavity ofthe porous structure.

FIG. 4 is a plan view of the anterior side of the interbody implant ofFIG. 1 showing a divider located in the internal cavity.

FIG. 5 is a plan view of the posterior side of the interbody implant ofFIG. 2 showing a posterior surface including a lattice structure.

FIG. 6 is a plan view of a medial-lateral side of the interbody implantof FIG. 5 showing a coupler.

FIG. 7 is a plan view of a superior-inferior side of the interbodyimplant of FIG. 4 showing superior-inferior alignment of latticestructures in the porous structure.

FIG. 8 is a cross-sectional view of the interbody implant taken atsection 8-8 of FIG. 5 showing a shape of the internal cavity.

FIG. 9 is a cross-sectional view of the interbody implant taken atsection 9-9 of FIG. 7 showing a wedge shape of a medial-lateral side ofthe interbody implant.

FIG. 10 is an exemplary perspective view of a portion of a porousstructure of interbody implants of the present disclosure showing aplurality of interconnected endless ligaments forming a plurality ofopen spaces.

FIG. 11 is a perspective view of another embodiment of an interbodyimplant of the present application.

FIG. 12 is a plan view of a medial-lateral side of the interbody implantof FIG. 11 showing a coupler.

FIG. 13 is a cross-sectional view of the interbody implant taken atsection 13-13 of FIG. 9 showing a shape of an internal cavity.

FIG. 14 is a perspective view of a Transforaminal Lumbar InterbodyFusion (TLIF) device.

FIG. 15 is a handle-end view of the TLIF device of FIG. 14.

FIG. 16 is an insertion-end view of the TLIF device of FIG. 14.

FIG. 17 is an anterior view of the TLIF device of FIG. 14.

FIG. 18 is a posterior view of the TLIF device of FIG. 14.

FIG. 19 is a superior view of the TLIF device of FIG. 14.

FIG. 20 is a cross-sectional view of the TLIF device of FIG. 19 taken atsection 20-20 looking rearward.

FIG. 21 is a cross-sectional view of the TLIF device of FIG. 19 taken atsection 21-21 looking forward.

FIG. 22 is a perspective view of a Posterior Lumbar Interbody Fusion(PLIF) device.

FIG. 23 is a handle-end view of the PLIF device of FIG. 22.

FIG. 24 is an insertion-end view of the PLIF device of FIG. 22.

FIG. 25 is a medial-lateral view of the PLIF device of FIG. 22.

FIG. 26 is a medial-lateral view of the PLIF device of FIG. 22.

FIG. 27 is a superior view of the PLIF device of FIG. 22.

FIG. 28 is a cross-sectional view of the PLIF device of FIG. 27 taken atsection 28-28 looking sideward.

FIG. 29 is a cross-sectional view of the PLIF device of FIG. 27 taken atsection 29-29 looking sideward.

FIG. 30 is a perspective view of an anatomic Anterior Cervical InterbodyFusion (ACIF) device comprising a porous structure and a solidstructure.

FIG. 31 is a side view of the ACIF device of FIG. 30.

FIG. 32 is bottom view of the ACIF device of FIG. 30.

FIG. 33 is a perspective view of the porous structure of the ACIF deviceof FIG. 30.

FIG. 34 is a perspective view of the solid structure of the ACIF deviceof FIG. 30.

FIG. 35 is a perspective view of a lordotic Anterior Cervical InterbodyFusion (ACIF) device comprising a porous structure and a solidstructure.

FIG. 36 is a side view of the ACIF device of FIG. 35.

FIG. 37 is bottom view of the ACIF device of FIG. 35.

FIG. 38 is a perspective view of the porous structure of the ACIF deviceof FIG. 35.

FIG. 39 is a perspective view of the solid structure of the ACIF deviceof FIG. 35.

In the drawings, which are not necessarily drawn to scale, like numeralsmay describe similar components in different views. Like numerals havingdifferent letter suffixes may represent different instances of similarcomponents. The drawings illustrate generally, by way of example, butnot by way of limitation, various embodiments discussed in the presentdocument.

DETAILED DESCRIPTION

FIG. 1 is an exploded perspective view of interbody implant 10 of thepresent application showing superior cage 24A, inferior cage 24B andporous structure 26. FIG. 2 is a perspective view of a posterior side ofinterbody implant 10 of FIG. 1. FIG. 3 is a perspective view of ananterior side of interbody implant 10 of FIGS. 1 and 2. FIGS. 1-3 arediscussed concurrently.

Interbody implant 10 can comprise anterior surface 12, posterior surface14, insertion surface 16, coupling surface 18, superior surface 20 andinferior surface 22. With reference to FIGS. 1-9, the presentapplication shows and describes a particular orientation of interbodyimplant 10. However, other orientations can be used. For example,superior surface 20 and inferior surface 22 can be reversed such thatcoupling surface 18 and insertion surface 16 can be on either the medialor lateral side of the spinal column; e.g., interbody implant 10 can berotated one-hundred-eighty degrees in the plane of FIG. 4. Likewise,anterior surface 12 can be used oriented toward a posterior of thepatient e.g., interbody implant 10 can be rotated one-hundred-eightydegrees in the plane of FIG. 7.

Surfaces 12-22 can be defined, at least partially, by superior cage 24A,inferior cage 24B and porous structure 26. Porous structure 26 candefine internal cavity 28, which can be divided by support wall 30 toform cavities 32A and 32B. In certain examples, internal cavity 28 canspan a majority of the width of interbody implant 10, such as byeliminating support wall 30. Anterior surface 12 can comprise openings34A and 34B into internal cavity 28. Superior surface 20 can includelattice structure 36, inferior surface 22 can include lattice structure38 and posterior surface 14 can include lattice structure 40.

Interbody implant 10 can be shaped for positioning between adjacentanatomic bodies, such as adjacent vertebrae in a spinal column.Interbody implant can be configured to occupy space where a degenerativeor damaged disk has been removed. As such, interbody implant 10 can beconfigured to directly contact bone, particularly at superior surface 20and inferior surface 22. For example, superior surface 20 can contactthe inferior surface of an upper vertebra and inferior surface 22 cancontact the superior surface of a lower vertebra. Interbody implant 10can be configured to promote bone in-growth into the surfaces ofinterbody implant 10 by inclusion of macro and micro pore structures.Porous structure 26 can include micro-pores by being made or fabricatedfrom porous material, such as Trabecular Metal™ or OsseoTi™, that caninclude pores on the scale of natural bone porosity, for example. Thematerial of porous structure 26 can additionally be shaped so thatporous structure 26 includes macro-pores, such as can be formed bylattice structures 36, 38 and 40. Additionally, porous structure 26 caninclude internal cavity 28, which can provide a space for holding bonegraft or other bone-growth-promoting materials to further promotein-growth of bone from the adjacent vertebrae.

In order to strengthen porous structure 26 to better withstand forcesapplied to interbody implant 10 when implanted between the adjacentvertebra, such as from bending and twisting of the spinal column,interbody implant 10 can be provided with one or both of cages 24A and24B. Superior cage 24A can extend around interbody implant 10 alongedges where superior surface 20 joins anterior surface 12, posteriorsurface 14, insertion surface 16 and coupling surface 18. Inferior cage24B can extend around interbody implant 10 along edges where inferiorsurface 22 joins anterior surface 12, posterior surface 14, insertionsurface 16 and coupling surface 18. Cages 24A and 24B can be curved orrounded, such as along a circular arc length in cross-section, to reduceor eliminate sharp edges. Cages 24A and 24B can be shaped and positionedto support porous structure 26, while also permitting interbody implant10 to retain the properties of porous structure 26, particularly thestiffness, resiliency and modulus of elasticity characteristics ofporous structure 26, such as in the superior-inferior S-I direction. Inembodiments, cages 24A and 24B can comprise cerclage structures thatcircumscribe porous structure 26 in transverse planes, but do notcontact each other in the superior-inferior direction. Thus, asdiscussed herein, interbody implant 10 can deform or compress in thesuperior-inferior direction according to the mechanical properties ofporous structure 26, thereby simulating biological bone-growthconditions in adjacent vertebrae.

In examples, porous structure 26 and cages 24A and 24B can be made ofseparate pieces that are attached together. For example, cages 24A and24B can be snap-fit onto porous structure 26, welded to porous structure26 or attached via an adhesive. In other examples, porous structure 26and cages 24A and 24B can be a monolithic structure. For example, porousstructure 26 and cages 24A and 24B can be made as a single, monolithicstructure using additive manufacturing processes.

With reference to FIG. 3, porous structure 26 can comprise superiorpanel 42, inferior panel 44 and middle panel 46. Middle panel 46 cancomprise insertion side portion 48, coupler side portion 50, posteriorportion 52 and support wall 30. Panels 42, 44 and 46 can be formed fromthe same piece of material so as to form a single, unitary, monolithicbody. As discussed below with respect to FIG. 10, porous structure 26can be formed by three-dimensional printing processes, a chemical vapordeposition process, and other procedures.

Superior cage 24A can comprise anterior leg 54A, posterior leg 56A,insertion leg 58A and coupler leg 60A. Inferior cage 24B can compriseanterior leg 54B, posterior leg 56B, insertion leg 58B and coupler leg60B. Legs 54A-60A can be configured to surround superior panel 42. Legs54B-60B can be configured to surround inferior panel 44. As such, theinner perimeters of superior cage 24A and inferior cage 24B can matchthe outer perimeters of superior panel 42 and inferior panel 44,respectively. The outer perimeters of superior cage 24A and inferiorcage 24B can match the outer perimeter of middle panel 46. Thesuperior-inferior height or thickness of superior cage 24A and inferiorcage 24B can match the superior-inferior height or thickness of superiorpanel 42 and inferior panel 44, respectively. Interior portions of legs54A-60B can include planar surfaces for engaging flush with panels 42,44 and 46, respectively. Exterior portions of legs 54A-60B can includecurved surfaces to facilitate sliding against tissue. When positionedaround panels 42 and 44, cages 24A and 24B can provide strength toporous structure 26 to, for example, prevent expansion of the materialof porous structure 26 in the transverse plane, which can protect thestructural integrity of lattice structures 36 and 38, for example.

As discussed below with reference to FIG. 6, coupler legs 60A and 60Bcan form portions of a socket for coupling to a tool, such as a threadedsocket for coupling with a shaft of an insertion tool. As discussedbelow with reference to FIG. 9, insertion legs 58A and 58B can be shapedto facilitate sliding of implant 10 between bodies such as adjacentvertebrae.

FIG. 4 is a plan view of the anterior side of interbody implant 10 ofFIGS. 1-3 showing divider 30 located between openings 34A and 34B tointernal cavity 28 of porous structure 26. FIG. 5 is a plan view of theposterior side of interbody implant 10 of FIGS. 1-3 showing posteriorsurface 14 including lattice structure 40. FIGS. 4 and 5 are discussedconcurrently.

Anterior surface 12 of implant 10 can be formed by a lower portion ofleg 54A of superior cage 24A, an upper portion of leg 54B of inferiorcage 24B and an anterior surface of porous structure 26. Posteriorsurface 14 of implant 10 can be formed by a lower portion of leg 56A ofsuperior cage 24A, an upper portion of leg 56B of inferior cage 24B anda posterior surface of porous structure 26. Surfaces 16 and 18 can beformed by lower portions of legs 58A and 60A of superior cage 24A,respectively, upper portions of legs 58B and 60B of inferior cage 24B,respectively, and medial-lateral surfaces of porous structure 26. Cages24A and 24B can be uncoupled in the superior-inferior direction and canthus be separated by a distance comprising a portion of the thickness ofporous structure 26. As such, downward or inferior pressure on implant10 will permit porous structure 26 to deform or compress withoutinterference from cages 24A and 24B.

Openings 34A and 34B can extend into the anterior surface of porousstructure 26 between cages 24A and 24B. In examples, thesuperior-inferior height of openings 34A and 34B can be approximatelyequal to the superior-inferior distance between changes 24A and 24B.Support wall 30 can be positioned between openings 34A and 34B.Interbody implant 10 can have a medial-lateral width W. In examples,support wall 30 can be positioned at a medial-lateral center ofinterbody implant 10. Cavities 32A and 32B can extend from openings 34Aand 34B to posterior portion 52 of middle panel 46 of porous structure26. As such, an anterior-posterior path through interbody implant 10 canbe formed by cavities 32A and 32B and lattice structure 40. As discussedin greater detail below with respect to FIGS. 7 and 8, lattice structure40 can comprise a plurality of openings within posterior portion 52extending from internal cavity 28 to the exterior of interbody implant10. Openings 24A and 24B provide access to internal cavity 28 for theplacement of bone graft material, bone cement or the like.

FIG. 6 is a plan view of a medial-lateral side of interbody implant 10of FIGS. 1-3 comprising coupling surface 18. Coupling surface 18 cancomprise socket 62, which can be defined by superior cage 24A andinferior cage 24B. Superior surface 20 and inferior surface 22 can bedisposed relative to each other at angle α. The angle α can facilitatefor interbody implant 10 inducing lordosis in the lumbar spine whenimplanted between lumbar vertebral bodies.

Socket 62 can be defined by superior segment 64A and inferior segment64B. As mentioned, each of segments 64A and 64B can form portions of asocket for coupling to a tool, such as a threaded socket for couplingwith a shaft of an insertion tool. As such segments 64A and 64B cancomprise circular arc segments. In an example, each of segments 64A and64B can form arc segments that are about one-hundred-sixty degrees. Invarious embodiments, each of segments 64A and 64B are less thanone-hundred-eighty degrees and are centered upon a common center suchthat segments 64A and 64B do not contact each other. As shown in FIGS.3, 7 and 8, segments 64A and 64B can be formed in legs 60A and 60B ofcages 24A and 24B. As shown in FIG. 3, legs 60A and 60B can includeflanges 66A and 66B, respectively, to provide axial (medial-lateral)length to segments 64A and 64B.

In different embodiments, the orientation between superior surface 20and inferior surface 22 can be selected and set such that angle α cancorrespond to a desired wedge angle (e.g., lordosis) between adjacentvertebrae. For example, interbody implant 10 depicted in FIGS. 1-9 canbe configured for use in the lower lumbar region of the spine betweenany of the L1-L5 vertebrae. In a particular example, interbody implant10 can be used between the L4 and L5 vertebrae or the L5 and S1vertebrae where the wedge angle can be in the range of about 6 degreesto about 10 degrees. However, in other embodiments, interbody implant 10can be configured for use in other regions of a spinal column and can beconfigured such that superior surface 20 and inferior surface 22 areapproximately parallel, such as is shown in FIG. 11-13. Furthermore, asdiscussed with reference to FIGS. 14-39, intervertebral implantsaccording to the present disclosure can be configured for insertion intothe spine at different levels and at different insertion approaches,e.g., anterior or posterior.

FIG. 7 is a plan view of a superior-inferior side of interbody implant10 of FIGS. 1-3 comprising inferior surface 22 showing superior-inferioralignment of lattice structure 38 in inferior panel 44 of in porousstructure 26 with lattice structure 36 (not visible in FIG. 7) insuperior panel 42 (not visible in FIG. 7) of porous structure 26. FIG. 8is a cross-sectional view of interbody implant 10 taken at section 8-8of FIG. 5 showing a shape of internal cavity 28 and the location oflattice structure 36 in superior panel 42. FIGS. 7 and 8 are discussedconcurrently.

As can be seen in FIG. 7, lattice structure 38 can align with latticestructure 36 in a superior-inferior direction such that edges of latticestructure 36 cannot be seen in porous structure 26. Alignment of latticestructures 36 and 38 can facilitate columnar growth of bone materialthrough interbody implant 10, which can, for example, strengthenosseointegration of interbody implant 10 with the adjacent vertebrae.

Lattice structure 38 can comprise a plurality of openings 68 that canextend from internal cavity 28 to the exterior of porous structure 26.In examples, each of openings 68 can comprise a hexa-lobular structurehaving six sides, or a portion of such a hexa-lobular structure. Inexamples, each hexa-lobular structure can have sides with differentlengths such that the hexa-lobular structures have an irregular shape.Such hexa-lobular structures can be advantageous in allowing bone growththrough panels 42 and 44, while not compromising the structuralintegrity of panels 42 and 44. Lattice structure 36 can comprise aplurality of openings 70 that can extend from internal cavity 28 to theexterior of porous structure 26. In examples, each of openings 70 can beconfigured in the same matter as openings 68. Likewise, openingsdefining lattice structure 40 in posterior portion 52 can be configuredsimilarly to openings 68.

As can be seen in FIG. 8, support wall 30 can have straight sidewallsthat can extend parallel to an anterior-posterior axis extending throughthe center of interbody implant 10. As mentioned above, such aconfiguration can facilitate positioning, e.g., centering, of interbodyimplant between adjacent vertebrae. Furthermore, cavities 32A and 32Bcan form generally rectilinear, e.g., square, chambers within porousstructure 26. However, cavities 32A and 32B can have any shape.

FIG. 9 is a cross-sectional view of interbody implant 10 taken atsection 9-9 of FIG. 7 showing a wedge shape of a medial-lateral side ofinterbody implant 10 comprising insertion surface 16. Insertion surface16 can be joined to superior surface 20 and inferior surface 22 bysegments 72A and 72B. Segments 72A and 72B can comprise portions of legs58A and 58B, respectively. Segments 72A and 72B can have flat exteriorsurfaces angled relative to centerline CL of interbody implant 10 atangles 13A and 13B. For example, segment 72A can be angled relative tocenterline CL at angle βB. Angle 13B can be in the range ofapproximately twenty to approximately forty degrees. Angle JA can beconfigured similarly to angle βB. Segments 72A and 72B can define thethinnest portion of the superior-inferior thickness of interbody implant10. Segments 72A and 72B can include rounded exterior surfaces tosmoothly blend segments 72A and 72B into superior surface 20, inferiorsurface 22 and coupling surface 18. The angling of segments 72A and 72Band the addition of curved edges can facilitate insertion of interbodyimplant 10 in between adjacent bodies, such as adjacent vertebrae.Segments 72A and 72B can thus provide the medial-lateral end ofinterbody implant 10 at coupling surface 18 with a wedge shape that canpush tissue out of the way while interbody implant 10 is slid in betweenvertebrae. The wedge shape can additionally provide distraction to theadjacent vertebrae. Segments 72A and 72B can have a medial-laterallength L1 that can extend toward the medial-lateral middle of interbodyimplant 10 to provide a smooth surface for sliding against tissue. L1can be greater than the thickness of legs 54A and 56A in theanterior-posterior direction, for example. Insertion side portion 48 caninclude superior segment 74A and inferior segment 74B that can extendlength L2 from segments 72A and 72B, respectively. Superior segment 74Aand inferior segment 74B, in addition to providing rigidity to porousstructure 26, can form lengths of flat, porous surfaces that can extendfrom segments 72A and 72B to guide interbody implant against adjacentbones. That is, segments 74A and 74B can contact surfaces of adjacentbones to orientate interbody implant 10 in a horizontal position betweenthe adjacent bones. Thus, segments 72A and 72B can clear tissue out ofthe way while segments 74A and 74B maintain the desired orientation ofinterbody implant to facilitate sliding. Segments 74A and 74B, whileporous, do not include edges from lattice structures 36 and 38 andthereby can reduce snagging on tissue while also allowing bone in-growthafter interbody implant 10 is fully implanted.

FIG. 10 is an exemplary perspective view of a portion of porousstructure 26 of interbody implant 10 showing a plurality ofinterconnected endless ligaments 80 forming a plurality of open spaces82.

Porous structure 26 can be formed of a suitable material that promotesbone in-growth and is biocompatible, such as porous metallic material,or a porous tantalum material. In examples, the porous material can havea porosity of approximately 20%-80% and pore sizes of approximately 50μm-600 μm. An example of highly porous tantalum and titanium alloymaterials is Trabecular Metal™ generally available from Zimmer Biomet,of Warsaw, Ind. Such a material may be formed from a reticulatedvitreous carbon foam substrate which is infiltrated and coated with abiocompatible metal, such as tantalum, by a chemical vapor deposition(CVD) process in the manner disclosed in detail in U.S. Pat. No.5,282,861 to Kaplan, the disclosure of which is expressly incorporatedherein by reference in its entirety for all purposes. In addition totantalum, other metals such as niobium, or alloys of tantalum andniobium with one another or with other metals may also be used.

In additional exemplary implementations, the porous metal structure canbe a formed from a titanium alloy using an additive manufacturingprocess, such as with OsseoTi™, which is commercially available fromZimmer Biomet, of Warsaw, Ind. Briefly, OsseoTi is highly biocompatible,has high corrosion resistance and includes a highly interconnectedporous architecture that mimics the porous structure of human cancellousbone, which can enhance bone integration and in-growth. In one exemplaryimplementation, the OsseoTi porous metal construct can include aporosity of 70%. OsseoTi™ material can be formed using athree-dimensional model of cancellous bone material as a template. Thetemplate can then be utilized to form any three-dimensionally printablestructure, such as the porous structure of interbody implant 10discussed herein.

In examples, porous structure 26 can be provided by any number ofsuitable three-dimensional, porous structures, and these structures canbe formed with one or more of a variety of materials including but notlimited to polymeric materials which are subsequently pyrolyzed, metals,metal alloys, ceramics. In some instances, a highly porousthree-dimensional structure will be fabricated using a selective lasersintering (SLS) or other additive manufacturing-type process such asdirect metal laser sintering. In one example, a three-dimensional porousarticle is produced in layer-wise fashion from a laser-fusible powder,e.g., a polymeric material powder or a metal powder, that is depositedone layer at a time. The powder is fused, remelted or sintered, by theapplication of laser energy, or energy from another source, that isdirected to portions of the powder layer corresponding to a crosssection of the article. After the fusing of the powder in each layer, anadditional layer of powder is deposited, and a further fusing step iscarried out, with fused portions or lateral layers fusing so as to fuseportions of previous laid layers until a three-dimensional article iscomplete. In certain embodiments, a laser selectively fuses powderedmaterial by scanning cross-sections generated from a 3-D digitaldescription of the article, e.g., from a CAD file or scan data, on thesurface of a powder bed. Net shape and near net shape constructs areinfiltrated and coated in some instances. Unfused material can beremoved from the completed component. Other types of rapid manufacturingprocesses can be used to fabricate the interbody implant, such as 3Dprinting processes.

Complex geometries can be created using such techniques. In someinstances, a three-dimensional porous structure will be particularlysuited for contacting bone and/or soft tissue, and in this regard, canbe useful as a bone substitute and as cell and tissue receptivematerial, for example, by allowing tissue to grow into the porousstructure over time to enhance fixation (i.e., osseointegration) betweenthe structure and surrounding bodily structures, for example, to providea matrix approximating natural cancellous bone or other bony structures.In this regard, a three-dimensional porous structure, or any regionthereof, may be fabricated to virtually any desired density, porosity,pore shape, and pore size (e.g., pore diameter). Such structurestherefore can be isotropic or anisotropic.

Such structures can be infiltrated and coated with one or more coatingmaterials. When coated with one or more biocompatible metals, anysuitable metal may be used including any of those disclosed herein suchas tantalum, titanium, a titanium alloy, cobalt chromium, cobaltchromium molybdenum, tantalum, a tantalum alloy, niobium, or alloys oftantalum and niobium with one another or with other metals. In variousexamples, a three-dimensional porous structure may be fabricated to havea substantial porosity, density, pore shape and/or void (pore) sizethroughout, or to comprise at least one of pore shape, pore size,porosity, and/or density being varied within the structure. For example,a three-dimensional porous structure to be infiltrated and coated mayhave a different pore shape, pore size and/or porosity at differentregions, layers, and surfaces of the structure.

In some embodiments, a non-porous or essentially non-porous basesubstrate will provide a foundation upon which a three-dimensionalporous structure will be built and fused thereto using a selective lasersintering (SLS) or other additive manufacturing-type process. Suchsubstrates can incorporate one or more of a variety of biocompatiblemetals such as titanium, a titanium alloy, cobalt chromium, cobaltchromium molybdenum, tantalum, or a tantalum alloy. In some examples,cages 24A and 24B can form a support structure when building (printing)porous structure 26.

The rapid manufacturing processes can be used to include a desired levelof porosity directly into porous structure 26. Likewise, latticestructures 36, 38 and 40 can be made to have any desired shape, size,number and aggregate strength and density in order to generatesufficient bonding strength to survive implantation and operation ofporous structure 26, while permitting infusion of bone from latticestructures 36, 38 and 40, as described herein. In examples, the size ofthe macro-pores described herein can be sized to the overall size of theporous structure. For example, the size of macro-pores 2323A-232F can bescaled to the overall footprint of porous structure 202. Likewise, theoverall cross-sectional surface areas of the various devices can bescaled as the height of the devices increases. For example, the size ofpocket 236 can increase as the height of porous structure 202 increases.

The porous structures described herein can have sufficient strength tosupport the weight of and forces generated by a spinal column. However,the greater the porosity of the structures, such as the larger thatinternal cavity 28 is or the larger the total volume of latticestructures 36, 38 and 40 are, the weaker the porous structure becomes.Thus, in a static environment, porous structure 26 is sufficientlystrong to support a spine. However, repeated compression and wear frommovement of the spine can, in some circumstances, generate stress withinthe porous structure, that, particularly in the transverse plane asmaterial of the porous structure is compressed by the spine. Edges ofthe porous structure can particularly become stressed. As such, with thedevices described herein, cages 24A and 24B can be provided and coupledto porous structure 26 to provide targeted strength to porous structure26. It has been found that, due to the inherent strength of porousstructure 26, not a lot of additional support is beneficial. As such, inembodiments, cages 24A and 24B can comprise only about 15% by volume ofinterbody implant 10 for the depicted embodiment of FIGS. 1-9. However,a greater or lesser volume can be used depending on where and how muchadditional strengthening is desired.

Interbody implant 10 can be implanted between adjacent bones, such asadjacent vertebrae, to promote bone in-growth. A method of implantinginterbody implant 10 can include properly preparing and performing alateral incision in a patient to access a medial or lateral portion of aspine adjacent an area where damaged or diseased intervertebral tissueis located. Soft tissue can be retracted using appropriateinstrumentation to provide better access to the damaged or diseasedintervertebral tissue. The damaged or diseased intervertebral tissue canbe removed using appropriate methods to clear access to inferior andsuperior bone surfaces of the adjacent vertebrae.

Bone-growth-promoting material can be packed into internal cavity 28. Invarious examples, bone-growth-promoting material can be packed intointernal cavity 28 before implantation. However, in some embodimentsdescribed herein, bone-growth-promoting material can be packed afterimplantation, such as in transverse designs. Interbody implant 10 can beattached to a tool, such as by threading a shaft of an insertioninstrument into socket 62. Interbody implant 10 can be manipulated by asurgeon, robot or another person to position insertion surface 16 in theincision. Interbody implant 10 can be oriented in a desired directionsuch that anterior surface 12 is pointed toward the anterior of thespine and posterior surface 14 is pointed toward the posterior of thespine. Segments 72A and 72B of cages 24A and 24B can be engaged withsoft tissue that is located medially or laterally of the implantationsite in the spine. The insertion tool can be pushed to slide soft tissueacross segments 72A and 72B. The angling of segments 72A and 72B canpush the soft tissue out of the way of interbody implant 10 to inhibitsoft tissue from scraping along lattice structures 36 and 38. Theinsertion tool can be pushed until segments 72A and 72B engage theexposed superior and inferior bone surfaces of the adjacent vertebraewhere disc material has been removed. Segments 72A and 72B can be pushedin between the adjacent vertebrae and can act as a wedge to help spreadthe vertebrae to receive the full thickness of interbody implant 10.Interbody implant 10 can continue to be pushed until lattice structures36 and 38 are positioned adjacent the exposed superior and inferior bonesurfaces of the adjacent vertebrae. Interbody implant 10 can bepositioned such that support wall 30 is centered on the vertebrae. Ifdeemed desirable by the surgeon to verify placement of interbody implant10, a surgeon can obtain imaging of the patient so that the location ofsupport wall 30 relative to the medial and lateral sides of thevertebrae can be viewed and measured. After interbody implant 10 ispositioned, the insertion tool can be removed from interbody implant 10and the incision in the patient can be appropriately closed to leaveinterbody implant 10 within the patient. The interbody implant 10 can beshaped for use in an anterior approach, a lateral approach, atransforaminal approach, or a posterior approach spinal fusion surgery.The examples illustrated herein are generally intended for lateral,transverse, posterior and anterior approaches.

With interbody implant 10 positioned between bone surfaces of theadjacent vertebrae, bone from the vertebrae can grow into themicro-pores of porous structure 26 and into the macro-pores formed bylattice structures 36, 38 and 40. The bone-growth-promoting materiallocated within internal cavity 28 can interact with the vertebrae toenhance bone growth. Furthermore, movement of the vertebrae, such as bybending and twisting of the spine, can apply compression to interbodyimplant 10. Because cages 24A and 24B are uncoupled in thesuperior-inferior direction, compressive forces applied to interbodyimplant 10 in the superior-inferior direction by the spine can betransmitted directly to porous structure 26. Porous structure 26 can beconfigured to have mechanical properties that replicate natural bone,e.g., stiffness, resiliency and modulus of elasticity. Thus, asdescribed herein compression of porous structure 26 can stimulatebiological growth of bone at the vertebrae contacting interbody implant10. As bone grows into interbody implant 10, the superior and inferiorvertebrae can become fused together through interbody implant 10.

FIG. 11 is a perspective view of interbody implant 90 comprising anotherembodiment of an interbody implant of the present application. FIG. 12is a plan view of a medial-lateral side of interbody implant 90 of FIG.11 showing coupler 92. FIG. 13 is a cross-sectional view of interbodyimplant 90 taken at section 13-13 of FIG. 9 showing a shape of internalcavity 94.

Interbody implant 90 can be configured in a similar manner as interbodyimplant 10 except that interbody implant 90 can have a shortermedial-lateral width, support wall 30 can be omitted, and superiorsurface 96 and inferior surface 98 can be generally parallel to eachother.

Interbody implant 90 can be configured for use in the thoracic region ofthe spine between any of the T1-T12 vertebrae. In a particular example,interbody implant 90 can be used between the T11 and T12 vertebrae.Dimensions of interbody implants described herein can be adjusted andchanged for use between any vertebrae in any region of the spine,including the cervical region, thoracic region and lumbar region.

The systems, devices and methods discussed in the present applicationcan be useful in manufacturing and implanting porous interbody implants,such as those that can be used in spinal correction procedures involvinglateral, transverse, anterior or posterior insertion of a spacer betweenadjacent vertebrae. The interbody implant can have micro and macroporosity to accept growth of bone into the implant. The material of theinterbody implant can inherently have a micro-porous structure and canbe shaped into having a macro-porous structure, wherein pores of themicro-porous structure can be large enough to accept bone in-growth andpores of the macro-porous structure can be small enough to enable thedevice to support adjacent bone structures. The material can compress tobiologically induce a human body into promoting bone growth in theimplant region of the body. The material of the interbody implant can bestrengthened by one or more cage-like or cerclage structures thatfacilitate cohesion of the interbody implant, such as in the transverseplane. The cage-like or cerclage structures can additionally betextured, e.g. to be smooth, and shaped, e.g., to include a wedge-shapedend, to facilitate insertion between vertebrae. The cage-like orcerclage structures can include superior and inferior portions that areuncoupled from each other to not interfere with superior-inferiorcompression of the material forming the micro and macro porousstructure. However, in additional examples, the cage-like or cerclagestructures can be directly coupled or attached to, for example, provideadditional strength.

FIGS. 1-13 illustrate an intervertebral implant configured for lateralapplications. FIGS. 14-39 illustrate other configurations ofintervertebral implants that can be made according to the presentdisclosure for different insertion approaches and for various levels ofthe spine. Specifically, FIGS. 14-21 show a Transforaminal LumbarInterbody Fusion (TLIF) device, FIGS. 22-29 show a Posterior LumbarInterbody Fusion (PLIF) device, FIGS. 30-34 show an anatomic AnteriorCervical Interbody Fusion (ACIF) device, and FIGS. 35-39 show a lordoticAnterior Cervical Interbody Fusion (ACIF) device. Features of thevarious configurations described herein can be combined. Eachconfiguration is suitable for producing a solid cerclage or cage-likestructure that can surround and support a micro-porous structure thatcan be integrally produced, such as with additive manufacturingtechniques, or separately produced. Each configuration is suitable forproducing intervertebral implants having desired compression or modulusof elasticity properties. Though the porous structure may be depicted orillustrated as having a different appearance with respect to specificembodiments, the porous structures described herein can comprise anyporous structure as described or referenced herein, such as with respectto FIG. 10.

FIG. 14 is a perspective view of Transforaminal Lumbar Interbody Fusion(TLIF) device 100 comprising porous structure 102 and cage 104. Cage 104can comprise handle-end 106, insertion-end 108, anterior side 110 andposterior side 112. Bone-facing surfaces 114 and 116 can comprisesuperior or inferior surfaces. Cage 104 can comprise tip 118, firstslide surface 120, second slide surface 122, posterior rails 124A and124B, anterior rails 126A and 126B, and socket 128. Socket 128 cancomprise transverse surfaces 130A and 130B, longitudinal surfaces 132Aand 132B, first and second bores 134A and 134B, and first and secondbosses 136A and 136B.

Superior wall 138 and inferior wall 142 can be disposed relative to eachother at angle α1. The angle α1 can facilitate for interbody implant 100inducing lordosis in the lumbar spine when implanted between lumbarvertebral bodies. In examples, angle α1 can be in the range of zero tothirty degrees. In the illustrated embodiment, angle α1 is approximatelyeight degrees.

Slide surfaces 120 and 122, rails 124A-126B and socket 128 can form acage-like structure as described herein for supporting porous structure102, as described herein. Porous structure 102 can comprise superiorwall 138, which, as shown in FIG. 19, can include macro-pores 140A,140B, 140C and 140D. Macro-pores 140A-140D can extend down throughinferior wall 142. Pocket 144 can be located between superior wall 138and inferior wall 142. Superior wall 138 and inferior wall 142 can beconnected by sidewalls 145A and 145B and anterior wall 146, which caninclude macro-pores 148A-148C. Additionally, pocket 144 can be providedwith one or more support walls, such as support wall 30 of FIGS. 1 and3.

FIG. 15 is a handle-end view of TLIF device 100 of FIG. 14 showingsocket 128. FIG. 16 is an insertion-end view of TLIF device 100 of FIG.14 showing tip 118. FIG. 17 is an anterior view of TLIF device 100 ofFIG. 14 showing anterior wall 146. FIG. 18 is a posterior view of TLIFdevice 100 of FIG. 14 showing socket 128. FIG. 19 is a superior view ofTLIF device 100 of FIG. 14 showing superior wall 138. FIG. 20 is across-sectional view of TLIF device 100 of FIG. 19 taken at section20-20 looking rearward to show pocket 144. FIG. 21 is a cross-sectionalview of TLIF device 100 of FIG. 19 taken at section 21-21 lookingforward to show anterior wall 146. FIGS. 14-21 are discussedconcurrently and mentioned specifically where applicable.

Porous structure 102 can be open on posterior side 112 to allowplacement of bone-growth material into porous structure 102 adjacentsuperior wall 138, inferior wall 142 and anterior wall 146. Thus,inferior wall 142, sidewall 145A, superior wall 138 and sidewall 145Bcan encircle the bone-growth material with anterior wall 146 inhibitingthe bone-growth material from freely passing through porous structure102. Furthermore, as shown in FIGS. 20 and 21, porous structure 102 cancomprise bump 147A for residing in detent 147B in cage 104.Additionally, cage 104 can comprise bump 149A for residing in detent149B in porous structure 102. Bumps 147A and 149A and detents 147B and149B can be configured to assist in retaining porous structure 102within cage 104, such as when porous structure 102 is not monolithicwith cage 104.

First slide surface 120 and second slide surface 122 can be angledrelative to bone-facing surfaces 114 and 116 and can be angled towardeach other near tip 118. In examples, the angle between first slidesurface 120 and second slide surface 122 can be in the range of 25degrees to 80 degrees. Likewise, anterior side 110 and posterior side112 can include slide surfaces 121 and 123 that can be curved to cometogether at tip 118. Tip 118 can be rounded to join anterior side 110and posterior side 112. Tip 118 can separate slide surfaces 120 and 122.As such, tip 118 can pointed to provide an insertion tip for penetratinginto and sliding past tissue, as described above. Rails 124A-126B cancurved to conform with the geometry of vertebrae. In examples, anteriorrails 126A and 126B can be curved in the posterior direction such thatanterior side 110 is convex, and posterior rails 124A and 124B can becurved in the posterior direction such that posterior side 112 isconcave. In examples, anterior side 110 and posterior side 112 can havea curvature that conforms with the anatomical curvature of the bodyportion of a vertebra. In examples, anterior side 110 and posterior side112 can be curved to provide contact with cortical bone of the bodyportion of the vertebra.

Socket 128 can form a port for receiving a tool that can be coupled toTLIF device 100 for insertion of TLIF device 100 between vertebrae.Socket 128 can permit the tool to be variably positioned relative tocage 104 to facilitate insertion of TLIF device 100. A tool can becoupled to cage via insertion of a pin through bores 134A and 134B toarticulate about pivot axis PA between longitudinal surfaces 132A and132B. In examples, bores 134A and 134B can be threaded. Transversesurfaces 130A and 130B can engage the tool throughout the range ofarticulation to maintain cage 104 parallel to the tool. In examples,longitudinal surfaces 132A and 132B can be disposed at angle θ (FIG. 19)relative to each other. In examples, angle θ can be in the range ofsixty to thirty degrees. In the illustrated embodiment, angle θ isapproximately forty-five degrees. In an example, longitudinal surface132B can be disposed parallel to insertion axis IA (FIG. 19). In anexample, longitudinal surface 132B can be coincident with insertion axisIA (FIG. 19). In another configuration, longitudinal surfaces 132A and132B can be made as part of porous structure 102 and tip 118 can includea slit or break so that rails 124A and 126A can be uncoupled from rails124B and 126B.

TLIF device 100 is configured for insertion in between vertebrae from aposterior side of the spinal column. More specifically, TLIF device 100is configured for insertion into a spinal column between a spinousprocess and an adjacent transverse process. TLIF device 100 can beconfigured, e.g., with different thicknesses, sized, widths, lengths toaccommodate usage at different levels in the spinal column or indifferent sized patients. TLIF device 100 can be rotated on axis PAwhile being inserted to position TLIF device 100 to extend across thespinal column. An insertion device can be coupled to handle-end 106 andinsertion-end 108 can be pushed through tissue into the spinal columnsuch that bone-facing surfaces 114 and 116 align with an inferiorsurface of a superior vertebra and a superior surface of an inferiorvertebra.

FIG. 22 is a perspective view of Posterior Lumbar Interbody Fusion(PLIF) device 150 comprising porous structure 152 and cage 154. Cage 154can comprise posterior handle-end 156, anterior insertion-end 158,medial-lateral side 160 and medial-lateral side 162. Bone-facingsurfaces 164 and 166 can comprise superior or inferior surfaces. Cage154 can comprise tip 168, first slide surface 170, second slide surface171, third slide surface 172, fourth slide surface 173, medial-lateralrails 174A and 174B, medial-lateral rails 176A and 176B, and socket face178. Socket face 178 can comprise bore 180 and notches 182A and 182B.

Slide surfaces 170-173, rails 174A-176B and socket face 178 can form acage-like structure as described herein for supporting porous structure152, as described herein. Porous structure 152 can comprise superiorwall 188, which, as shown in FIG. 27, can include macro-pores 190A,190B, 190C, 190D and 190E. Macro-pores 190A-190E can extend down throughinferior wall 192. Pocket 194 can be located between superior wall 188and inferior wall 192. Superior wall 188 and inferior wall 192 can beconnected by sidewalls 195A and 195B anterior wall 196, which caninclude macro-pores 198A-198D. Additionally, pocket 194 can be providedwith one or more support walls, such as support wall 30 of FIGS. 1 and3.

FIG. 23 is a handle-end view of PLIF device 150 of FIG. 22 showingsocket face 178. FIG. 24 is an insertion-end view of PLIF device 150 ofFIG. 22 showing tip 168. FIG. 25 is a medial-lateral view of PLIF deviceof 150 FIG. 22 showing pocket 194 medial-lateral wall 196. FIG. 26 is amedial-lateral view of PLIF device 150 of FIG. 22 showing pocket 194medial-lateral wall 196. FIG. 27 is a superior view of PLIF device 150of FIG. 22 showing superior wall 188. FIG. 28 is a cross-sectional viewof PLIF device 150 of FIG. 27 taken at section 28-28 looking sideward toshow medial-lateral wall 196. FIG. 29 is a cross-sectional view of PLIFdevice 150 of FIG. 27 taken at section 29-29 looking sideward to showpocket 194. FIGS. 22-29 are discussed concurrently and mentionedspecifically where applicable.

Porous structure 152 can be open on medial-lateral side 162 to allowplacement of bone-growth material into porous structure 152 adjacentsuperior wall 188, inferior wall 192 and medial-lateral wall 196. Thus,inferior wall 192, sidewall 195A, superior wall 188 and sidewall 195Bcan encircle the bone-growth material with medial-lateral wall 196inhibiting the bone-growth material from freely passing through porousstructure 152. Furthermore, as shown in FIGS. 28 and 29, porousstructure 152 can comprise bump 197A for residing in detent 197B in cage104. Bump 197A and detent 197B can be configured to assist in retainingporous structure 152 within cage 154 such as when porous structure 152is not monolithic with cage 154. Likewise, notches 182A and 182B can beused to support porous structure 152 and can permit growth of boneymaterial into the interior of cage 154.

Second slide surface 171 and fourth slide surface 173 can be angledrelative to medial-lateral sides 160 and 162 and can be angled towardeach other near tip 168. Likewise, first slide surface 170 and thirdslide surface 172 can be angled relative to bone-facing surfaces 164 and166 to come together at tip 168. Tip 168 can be rounded to join slidesurfaces 170 and 172. Tip 168 can separate slide surfaces 171 and 173.As such, tip 168 can be pointed to provide an insertion tip forpenetrating into and sliding past tissue, as described above. In anexample, tip 168 has a pyramid shape and rails 174A-176B can have aright trapezoidal shape. Rails 174A-176B can be straight. In examples,medial-lateral rails 176A and 176B can be straight in the medial-lateraldirection such that anterior side 160 is planer, and medial-lateralrails 174A and 174B can be straight in the medial-lateral direction suchthat posterior side 162 is planer.

As shown in FIGS. 25 and 26, slide surfaces 170 and 172 can be angledrelative to each other at angle σ1. In examples, angle σ1 can be in therange of forty to ninety degrees. In the illustrated embodiment, angleσ1 is approximately forty degrees.

Similarly, as shown in FIG. 27 slide surfaces 171 and 173 can be angledto each other at angle σ2. In examples, angle σ2 can be in the range offorty-five to seventy-five degrees. In the illustrated embodiment, angleσ2 is approximately sixty degrees.

As shown in FIGS. 25 and 26, superior-inferior bone-facing surfaces 166and 164 can be angled (e.g., lordosis) relative to each other at angleσ3. In examples, angle σ3 can be in the range of zero to thirty degrees.In the illustrated embodiment, angle σ3 is approximately twenty degrees.

As shown in FIG. 27, medial-lateral sides 160 and 162 can be angledrelative to each other at angle σ4. In examples, angle σ4 can be in therange of zero to twenty degrees. In the illustrated embodiment, angle σ4is approximately fifteen degrees.

Bore 180 of socket face 178 can form a port for receiving a tool thatcan be coupled to PLIF device 150 for insertion of PLIF device 150between vertebrae. Bore 180 can permit the tool to be secured to cage154 to facilitate insertion of PLIF device 150. Bore 180 can be locatedin socket face 178, which can be configured to couple rails 174A and176A to rails 174B and 176B. In another configuration, socket face 178can be made as part of porous structure 152 and tip 168 can include aslit or break so that rails 174A and 176A can be uncoupled from rails174B and 176B.

PLIF device 150 is configured for insertion in between vertebrae from aposterior side of the spinal column. More specifically, PLIF device 150is configured for insertion into a spinal column between a spinousprocess and an adjacent transverse process. PLIF device 150 can beconfigured, e.g., with different thicknesses, sized, widths, lengths toaccommodate usage at different levels in the spinal column or indifferent sized patients. PLIF device 150 can inserted straight into thespinal column on one side of the spinal cord. In examples, a second PLIFdevice 150 can be inserted straight into the spinal column on theopposite side of the spinal column. An insertion device can be coupledto handle-end 156 and anterior end 158 can be pushed through tissue intothe spinal column such that bone-facing surfaces 164 and 166 align withan inferior surface of a superior vertebra and a superior surface of aninferior vertebra.

FIG. 30 is a perspective view of anatomic Anterior Cervical InterbodyFusion (ACIF) device 200 comprising porous structure 202 and solidstructure 204. Solid structure 204 can comprise anterior handle-end 206,posterior insertion-end 208, medial-lateral side 210 and medial-lateralside 212. Bone-facing surfaces 214 and 216 can comprise superior orinferior surfaces. Solid structure 204 can comprise tip 218, superiorrails 220A, 220B, 220C and 220D, inferior rails 222A, 222B, 222C and222D and socket 224.

Rails 220A-220D, rails 222A-222D and socket 224 can form a cage-likestructure as described herein for supporting porous structure 202, asdescribed herein. Porous structure 202 can comprise superior wall 230,which, as shown in FIG. 32, can include macro-pores 232A, 232B, 232C,232D, 232E and 232F. Macro-pores 232A-232F can extend down throughinferior wall 234. Pocket 236 can be located between superior wall 230and inferior wall 234 and can extend all the way across porous structure202. However, only one medial-lateral side of porous structure 202 canhave an opening for pocket 236. Superior wall 230 and inferior wall 234can be connected by anterior wall 238A and posterior wall 238B.Additionally, pocket 236 can be provided with one or more support walls,such as support wall 30 of FIGS. 1 and 3.

FIG. 31 is a side view of ACIF device 200 of FIG. 30 showing pocket 236.FIG. 32 is bottom view of ACIF device 200 of FIG. 30 showing macro-pores232A-232F. FIG. 33 is a perspective view of porous structure 202 of ACIFdevice 200 of FIG. 30 showing superior wall 230 and inferior wall 234bounding pocket 236. FIG. 34 is a perspective view of solid structure204 of ACIF device 200 of FIG. 30 showing rails 220A-222D. FIGS. 30-34are discussed concurrently and mentioned specifically where applicable.

Porous structure 202 can be open on medial-lateral sides 210 and 212 toallow placement of bone-growth material into porous structure 202adjacent superior wall 230 and inferior wall 234. Thus, inferior wall234, anterior wall 238A, superior wall 230 and posterior wall 238B canencircle the bone-growth material within pocket 236. Furthermore, asshown in FIG. 33, porous structure 202 can comprise superior shoulder240A and inferior shoulder 240B, which can be configured to assist inretaining porous structure 202 within solid structure 204, such as byproducing a snap-fit interface or surfaces for forming a weld or forproviding increased surface area for porous structure 202 to join tosolid structure 204 such as when porous structure 202 is not monolithicwith solid structure 204.

ACIF device 200 can be shaped for use in the anatomic or non-lordoticregions of the spinal column. However, ACIF device 200 can be configuredto provide a lordosis correction of 6 degrees. ACIF device 200 cancomprise a generally rectilinear body with medial-lateral side 210,medial-lateral side 212, bone-facing surface 216 including inferior wall234, anterior wall 238A and posterior wall 238B being generally flat.Anterior wall 238A can be disposed at right angles to bone-facingsurfaces 214 and 216 and medial-lateral sides 210 and 212. Posteriorwall 238B can be disposed at right angles to bone-facing surfaces 214and 216 and medial-lateral sides 210 and 212. However, medial-lateralsides 210 and 212 can be curved to blend into posterior wall 238B. In anexample, surfaces 244A and 244B can comprise circular arc segments. Inexamples, surfaces 294A and 294B can be circular quadrants. Bone-facingsurface 214 including superior wall 230 can be curved or hump-shaped,such as to fit against the natural curvature of the inferior side of avertebra thereby increasing surface area contact to promote bonein-growth. Anterior wall 238A can be shorter than posterior wall 238B.As such, ACIF device 200 can be shaped to be pushed through tissue.

Socket 224 can form a port for receiving a tool that can be coupled toACIF device 200 for insertion of ACIF device 200 between vertebrae.Socket 224 can include bore 242 that can permit the tool to be securedto solid structure 204 to facilitate insertion of ACIF device 200. Bore242 can comprise a threaded port. Socket 224 can additionally includefeatures to prevent movement of socket 224 relative to porous structure202. For example, socket 224 can include lobes 246A and 246B. Inexamples, socket 224 can be attached to rails 220B and 222B. In otherexamples, socket 224 can be spaced from rails 220B and 222B.

ACIF device 200 is configured for insertion in between vertebrae from ananterior side of the spinal column. More specifically, ACIF device 200is configured for insertion into a spinal column, from an anterior orfront approach, straight between the main bodies of adjacent vertebraein the lower cervical spine region. ACIF device 200 can be configured,e.g., with different thicknesses, sized, widths, lengths to accommodateusage at different levels in the spinal column or in different sizedpatients. An insertion device can be coupled to handle-end 206 andposterior end 208 can be pushed through tissue into the spinal columnsuch that bone-facing surfaces 214 and 216 align with an inferiorsurface of a superior vertebra and a superior surface of an inferiorvertebra, such that ACIF device 200 can align with the posterior wall ofthe adjacent vertebrae. ACIF device 200 can be produced in differentsizes, e.g., thicknesses of porous structure 202, for use in differentlevels of the spine.

FIG. 35 is a perspective view of lordotic Anterior Cervical InterbodyFusion (ACIF) device 250 comprising porous structure 252 and solidstructure 254. Solid structure 254 can comprise anterior handle-end 256,posterior insertion-end 258, medial-lateral side 260 and medial-lateralside 262. Bone-facing surfaces 264 and 266 can comprise superior orinferior surfaces. Solid Structure 254 can comprise tip 268, superiorrails 270A, 270B, 270C and 270D, inferior rails 272A, 272B, 272C and272D and socket 274.

Rails 270A-270D, rails 272A-272D and socket 274 can form a cage-likestructure as described herein for supporting porous structure 252, asdescribed herein. Porous structure 252 can comprise superior wall 280,which, as shown in FIG. 37, can include macro-pores 282A, 282B, 282C,282D, 282E and 282F. Macro-pores 282A-282F can extend down throughinferior wall 284. Pocket 286 can be located between superior wall 280and inferior wall 284 and can extend all the way across porous structure252. As described above, the scale of macro-pores 282A-282F and the sizeof pocket 286 can be scaled to the size of porous structure 252, suchthat the larger porous structure is, the greater macro-pores 282A-282Fand pocket 286 can be. However, only one medial-lateral side of porousstructure 252 can have an opening for pocket 286. Superior wall 280 andinferior wall 284 can be connected by anterior wall 288A and posteriorwall 288B. Additionally, pocket 286 can be provided with one or moresupport walls, such as support wall 30 of FIGS. 1 and 3.

FIG. 36 is a side view of ACIF device 250 of FIG. 35 showing pocket 286.FIG. 37 is bottom view of ACIF device 250 of FIG. 35 showing macro-pores282A-282F. FIG. 38 is a perspective view of porous structure 252 of ACIFdevice 250 of FIG. 35 showing superior wall 280 and inferior wall 234bounding pocket 286. FIG. 39 is a perspective view of solid structure254 of ACIF device 250 of FIG. 35 showing rails 270A-272D. FIGS. 35-39are discussed concurrently and mentioned specifically where applicable.

Porous structure 252 can be open on medial-lateral sides 260 and 262 toallow placement of bone-growth material into porous structure 252adjacent superior wall 280 and inferior wall 284. Thus, inferior wall284, anterior wall 288A, superior wall 280 and posterior wall 288B canencircle the bone-growth material within pocket 286. Furthermore, asshown in FIG. 38, porous structure 252 can comprise superior shoulder290A and inferior shoulder 290B, which can be configured to assist inretaining porous structure 252 within solid structure 254, such as byproducing a snap-fit interface or surfaces for forming a weld or forproviding increased surface area for porous structure 252 to join tosolid structure 254 such as when porous structure 252 is not monolithicwith solid structure 254.

ACIF device 250 can be shaped for use in the lordotic regions of thespinal column. ACIF device 250 can be configured to provide a lordosiscorrection of 6 degrees. ACIF device 250 can comprise a generallyrectilinear body with medial-lateral side 260, medial-lateral side 262,bone-facing surface 264 including superior wall 286, bone-facing surface266 including inferior wall 284, anterior wall 288A and posterior wall288B being generally flat. Anterior wall 288A can be disposed at rightangles to bone-facing surfaces 264 and 266 and medial-lateral sides 260and 262. Posterior wall 288B can be disposed at right angles tobone-facing surfaces 264 and 266 and medial-lateral sides 260 and 262.However, medial-lateral sides 260 and 262 can be curved to blend intoposterior wall 288B. In an example, surfaces 294A and 294B can comprisecircular arc segments. In examples, surfaces 294A and 294B can becircular quadrants. Bone-facing surface 264 including superior wall 280and bone-facing surface 266 including inferior wall 284 can be flat,such as to fit against the natural curvature of the inferior andsuperior sides of adjacent vertebrae in the lordotic region of the spinethereby increasing surface area contact to promote bone in-growth.Anterior wall 288A can be shorter than posterior wall 288B. As such,ACIF device 250 can be shaped to be pushed through tissue.

Socket 274 can form a port for receiving a tool that can be coupled toACIF device 250 for insertion of ACIF device 250 between vertebrae.Socket 274 can include bore 292 that can permit the tool to be securedto solid structure 254 to facilitate insertion of ACIF device 250. Bore292 can comprise a threaded port. Socket 274 can additionally includefeatures to prevent movement of socket 274 relative to porous structure252. For example, socket 274 can include lobes 296A and 296B. Inexamples, socket 274 can be attached to rails 270B and 272B. In otherexamples, socket 274 can be spaced from rails 270B and 272B.

ACIF device 250 is configured for insertion in between vertebrae from ananterior side of the spinal column. More specifically, ACIF device 250is configured for insertion into a spinal column, from an anterior orfront approach, straight between the main bodies of adjacent vertebraein the lower cervical spine region. ACIF device 250 can be configured,e.g., with different thicknesses, sized, widths, lengths to accommodateusage at different levels in the spinal column or in different sizedpatients. ACIF device 250 can inserted straight into the spinal columndirectly in front of the spinal column. An insertion device can becoupled to handle-end 256 and posterior end 258 can be pushed throughtissue into the spinal column such that bone-facing surfaces 264 and 266align with an inferior surface of a superior vertebra and a superiorsurface of an inferior vertebra, such that ACIF device 200 can alignwith the posterior wall of the adjacent vertebrae. ACIF device 250 canbe produced in different sizes, e.g., thicknesses of porous structure252, for use in different levels of the spine.

Various Notes & Examples

Example 1 can include or use subject matter such as an interbody implantcomprising a first cage comprising an anterior segment, a medialsegment, a posterior segment and a lateral segment contiguouslyconnected to each other to define an interior space; and a porousstructure located in the interior space and bounded by the cage, theporous structure comprising opposed superior and inferior surfacesexposed through the first cage; an internal cavity located in aninterior of the porous structure; and a plurality of ports connectingthe internal cavity to the superior and inferior surfaces.

Example 2 can include, or can optionally be combined with the subjectmatter of Example 1, to optionally include a porous structure that canfurther comprise an anterior-posterior opening into the internal cavity.

Example 3 can include, or can optionally be combined with the subjectmatter of one or any combination of Examples 1 or 2 to optionallyinclude an anterior-posterior opening that can be located on an anteriorsurface of the porous structure.

Example 4 can include, or can optionally be combined with the subjectmatter of one or any combination of Examples 1 through 3 to optionallyinclude a porous structure that can further comprise a posterior surfaceincluding a plurality of ports.

Example 5 can include, or can optionally be combined with the subjectmatter of one or any combination of Examples 1 through 4 to optionallyinclude a porous support wall extending across the internal cavity in asuperior-inferior direction.

Example 6 can include, or can optionally be combined with the subjectmatter of one or any combination of Examples 1 through 5 to optionallyinclude a support wall that can be located at a medial-lateral center ofthe interbody implant.

Example 7 can include, or can optionally be combined with the subjectmatter of one or any combination of Examples 1 through 6 to optionallyinclude a plurality of ports that can comprise a plurality ofhexa-lobular openings extending from an exterior of the porous structureto the internal cavity.

Example 8 can include, or can optionally be combined with the subjectmatter of one or any combination of Examples 1 through 7 to optionallyinclude each of the plurality of ports comprising a cross-sectional arealarger than a pore size of the porous structure.

Example 9 can include, or can optionally be combined with the subjectmatter of one or any combination of Examples 1 through 8 to optionallyinclude a porous structure that can comprise a plurality of ligamentsdefining open spaces therebetween, the ligaments forming a matrix ofcontinuous channels having no dead ends.

Example 10 can include, or can optionally be combined with the subjectmatter of one or any combination of Examples 1 through 9 to optionallyinclude a second cage having anterior, medial, posterior and lateralsegments contiguously connected to each other to define an additionalinterior space, wherein the porous structure can be located within theadditional interior space.

Example 11 can include, or can optionally be combined with the subjectmatter of one or any combination of Examples 1 through 10 to optionallyinclude a first cage and a second cage that can be uncoupled in asuperior-inferior direction.

Example 12 can include, or can optionally be combined with the subjectmatter of one or any combination of Examples 1 through 11 to optionallyinclude a threaded socket located on a medial or lateral side of theinterbody implant, the threaded socket having a superior portion locatedon the first cage and an inferior portion located on the second cage.

Example 13 can include, or can optionally be combined with the subjectmatter of one or any combination of Examples 1 through 12 to optionallyinclude a wedge structure located on an end of the interbody implant.

Example 14 can include, or can optionally be combined with the subjectmatter of one or any combination of Examples 1 through 13 to optionallyinclude a wedge structure that can comprise opposing tapered surfacesthat form a thinnest portion of the interbody implant in asuperior-inferior direction.

Example 15 can include, or can optionally be combined with the subjectmatter of one or any combination of Examples 1 through 14 to optionallyinclude a first cage that can define a superior-most surface of theinterbody implant flush with a superior-most portion of the porousstructure, and a second cage that can define an inferior-most surface ofthe interbody implant flush with an inferior-most portion of the porousstructure.

Example 16 can include, or can optionally be combined with the subjectmatter of one or any combination of Examples 1 through 15 to optionallyinclude an interbody implant that can define an angle between thesuperior-most surface and the inferior-most surface.

Example 17 can include, or can optionally be combined with the subjectmatter of one or any combination of Examples 1 through 16 to optionallyinclude an angle that can be in the range of approximately six degreesto approximately thirty degrees.

Example 18 can include, or can optionally be combined with the subjectmatter of one or any combination of Examples 1 through 17 to optionallyinclude anterior segments of first and second cages that can be curvedso that an anterior side of the interbody implant is convex, andposterior segments of the first and second cages can be curved so that aposterior side of the interbody implant is concave.

Example 19 can include, or can optionally be combined with the subjectmatter of one or any combination of Examples 1 through 18 to optionallyinclude a first cage and a second cage that can be connected by asocket.

Example 20 can include, or can optionally be combined with the subjectmatter of one or any combination of Examples 1 through 19 to optionallyinclude a superior wall that can have a bore, an inferior wall that canhave a bore, a first longitudinal surface connecting the superior andinferior walls, and a second longitudinal surface connecting thesuperior and inferior walls, wherein the first and second longitudinalsurfaces can be disposed at an angle to each other.

Example 21 can include, or can optionally be combined with the subjectmatter of one or any combination of Examples 1 through 20 to optionallyinclude a first cage and a second cage that can be angled toward eachother at an insertion end of the interbody implant and the first cageand the second cage can come together at a rounded tip at the insertionend.

Example 22 can include, or can optionally be combined with the subjectmatter of one or any combination of Examples 1 through 21 to optionallyinclude an insertion end and a coupling end, and a first cage and asecond cage that can be joined at the insertion end and the couplingend.

Example 23 can include, or can optionally be combined with the subjectmatter of one or any combination of Examples 1 through 22 to optionallyinclude an insertion end that can comprise a pyramid and a coupling endthat can include a socket.

Example 24 can include, or can optionally be combined with the subjectmatter of one or any combination of Examples 1 through 23 to optionallyinclude an insertion end that can be thicker than a coupling end.

Example 25 can include, or can optionally be combined with the subjectmatter of one or any combination of Examples 1 through 24 to optionallyinclude a socket piece embedded into the porous structure.

Example 26 can include, or can optionally be combined with the subjectmatter of one or any combination of Examples 1 through 25 to optionallyinclude a socket piece that can be connected to a first cage and asecond cage.

Example 27 can include, or can optionally be combined with the subjectmatter of one or any combination of Examples 1 through 26 to optionallyinclude a superior surface of the porous structure that can be curved.

Example 28 can include, or can optionally be combined with the subjectmatter of one or any combination of Examples 1 through 27 to optionallyinclude a superior-inferior stiffness of the interbody implant isdefined by the porous structure.

Example 29 can include, or can optionally be combined with the subjectmatter of one or any combination of Examples 1 through 28 to optionallyinclude a first cage that can be fabricated from a solid metal materialand a porous structure that can be fabricated from a porous metalmaterial having a porosity mimicking that of natural bone.

Example 30 can include, or can optionally be combined with the subjectmatter of one or any combination of Examples 1 through 29 to optionallyinclude a first cage that can comprise about 15% by volume of theinterbody implant.

Example 31 can include or use subject matter such as a method ofimplanting an interbody implant between adjacent bones to promote bonein-growth and the method can comprise inserting the interbody implantbetween adjacent bones, the interbody implant comprising a porousstructure comprising a monolithic body formed of a porous materialreplicating porosity of human bone; an interior cavity; and a pluralityof openings in the monolithic body extending from the interior cavity toan exterior of the monolithic body; and a cage structure circumscribinga portion of the monolithic body in a transverse plane; positioning theplurality of openings against surfaces of the bones to allow forin-growth; and permitting the porous structure to compress in asuperior-inferior direction between the bones and within the cagestructure to stimulate biological bone growth within the bones.

Example 32 can include, or can optionally be combined with the subjectmatter of Example 31, to optionally include inserting the interbodyimplant between adjacent bones by sliding a wedge-shaped medial-lateralend of the interbody implant along tissue surrounding the bones.

Example 33 can include, or can optionally be combined with the subjectmatter of one or any combination of Examples 31 or 32 to optionallyinclude disposing bone cement or bone graft material within the interiorcavity before inserting the interbody implant between adjacent bones.

Example 34 can include, or can optionally be combined with the subjectmatter of one or any combination of Examples 31 through 33 to optionallyinclude inserting the interbody implant between adjacent bones byattaching a tool to a socket located on a medial-lateral end of theinterbody implant, the socket formed entirely in the cage structure.

Example 35 can include, or can optionally be combined with the subjectmatter of one or any combination of Examples 31 through 34 to optionallyinclude a cage structure that can comprise: a first cage defining asuperior-most surface of the interbody implant flush with asuperior-most portion of the porous structure; and a second cagedefining an inferior-most surface of the interbody implant flush with aninferior-most portion of the porous structure; wherein the first cageand the second cage are separated in a superior-inferior direction anddo not contact each other.

Example 36 can include, or can optionally be combined with the subjectmatter of one or any combination of Examples 31 through 35 to optionallyinclude permitting the porous structure to compress in asuperior-inferior direction between the bones and within the cagestructure by compressing the porous structure via movement of the bones.

Example 37 can include, or can optionally be combined with the subjectmatter of one or any combination of Examples 31 through 36 to optionallyinclude inserting the interbody implant between adjacent bones byinserting the interbody implant such that a support wall within theinterior cavity is medially-laterally centered between the adjacentbones.

Example 38 can include or use subject matter such as an intervertebralimplant for lateral insertion and the intervertebral implant cancomprise a porous structure formed of a porous material, the porousstructure shaped to define an interior cavity; and a plurality oflongitudinal passages extending through the porous structure tointersect the internal cavity; a first cerclage cage horizontallysurrounding the porous structure; and a second cerclage cagehorizontally surrounding the porous structure uncoupled from the firstcerclage cage such that a longitudinal stiffness of the intervertebralimplant is defined by the porous structure.

Example 39 can include, or can optionally be combined with the subjectmatter of Example 38, to optionally include a porous structure that cancomprise a superior panel including a plurality of openings extendingthrough the superior panel to partially define the plurality oflongitudinal passages; an inferior panel including a plurality ofopenings extending through the inferior panel to partially define theplurality of longitudinal passages; and a middle panel separating thesuperior panel and the inferior panel to define the interior cavity.

Example 40 can include, or can optionally be combined with the subjectmatter of one or any combination of Examples 38 or 39 to optionallyinclude a first cerclage cage and a second cerclage cage that caninclude ramped end portions to provide the intervertebral implant with awedge-shaped insertion end.

Example 41 can include, or can optionally be combined with the subjectmatter of one or any combination of Examples 38 through 40 to optionallyinclude a first cerclage cage and a second cerclage cage that can eachinclude a partial coupling socket that together form a socket configuredto receive an insertion tool.

Each of these non-limiting examples can stand on its own, or can becombined in various permutations or combinations with one or more of theother examples.

The above detailed description includes references to the accompanyingdrawings, which form a part of the detailed description. The drawingsshow, by way of illustration, specific embodiments in which theinvention can be practiced. These embodiments are also referred toherein as “examples.” Such examples can include elements in addition tothose shown or described. However, the present inventor alsocontemplates examples in which only those elements shown or describedare provided. Moreover, the present inventor also contemplates examplesusing any combination or permutation of those elements shown ordescribed (or one or more aspects thereof), either with respect to aparticular example (or one or more aspects thereof), or with respect toother examples (or one or more aspects thereof) shown or describedherein.

In the event of inconsistent usages between this document and anydocuments so incorporated by reference, the usage in this documentcontrols.

In this document, the terms “a” or “an” are used, as is common in patentdocuments, to include one or more than one, independent of any otherinstances or usages of “at least one” or “one or more.” In thisdocument, the term “or” is used to refer to a nonexclusive or, such that“A or B” includes “A but not B,” “B but not A,” and “A and B,” unlessotherwise indicated. In this document, the terms “including” and “inwhich” are used as the plain-English equivalents of the respective terms“comprising” and “wherein.” Also, in the following claims, the terms“including” and “comprising” are open-ended, that is, a system, device,article, composition, formulation, or process that includes elements inaddition to those listed after such a term in a claim are still deemedto fall within the scope of that claim. Moreover, in the followingclaims, the terms “first,” “second,” and “third,” etc. are used merelyas labels, and are not intended to impose numerical requirements ontheir objects.

Method examples described herein can be machine or computer-implementedat least in part. Some examples can include a computer-readable mediumor machine-readable medium encoded with instructions operable toconfigure an electronic device to perform methods as described in theabove examples. An implementation of such methods can include code, suchas microcode, assembly language code, a higher-level language code, orthe like. Such code can include computer readable instructions forperforming various methods. The code may form portions of computerprogram products. Further, in an example, the code can be tangiblystored on one or more volatile, non-transitory, or non-volatile tangiblecomputer-readable media, such as during execution or at other times.Examples of these tangible computer-readable media can include, but arenot limited to, hard disks, removable magnetic disks, removable opticaldisks (e.g., compact disks and digital video disks), magnetic cassettes,memory cards or sticks, random access memories (RAMs), read onlymemories (ROMs), and the like.

The above description is intended to be illustrative, and notrestrictive. For example, the above-described examples (or one or moreaspects thereof) may be used in combination with each other. Otherembodiments can be used, such as by one of ordinary skill in the artupon reviewing the above description. The Abstract is provided to complywith 37 C.F.R. § 1.72(b), to allow the reader to quickly ascertain thenature of the technical disclosure. It is submitted with theunderstanding that it will not be used to interpret or limit the scopeor meaning of the claims. Also, in the above Detailed Description,various features may be grouped together to streamline the disclosure.This should not be interpreted as intending that an unclaimed disclosedfeature is essential to any claim. Rather, inventive subject matter maylie in less than all features of a particular disclosed embodiment.Thus, the following claims are hereby incorporated into the DetailedDescription as examples or embodiments, with each claim standing on itsown as a separate embodiment, and it is contemplated that suchembodiments can be combined with each other in various combinations orpermutations. The scope of the invention should be determined withreference to the appended claims, along with the full scope ofequivalents to which such claims are entitled.

The claimed invention is:
 1. An interbody implant comprising: a firstcage comprising an anterior segment, a medial segment, a posteriorsegment and a lateral segment contiguously connected to each other todefine an interior space; and a porous structure located in the interiorspace and bounded by the cage, the porous structure comprising: opposedsuperior and inferior surfaces exposed through the first cage; aninternal cavity located in an interior of the porous structure; and aplurality of ports connecting the internal cavity to the superior andinferior surfaces.
 2. The interbody implant of claim 1, wherein theporous structure further comprises an anterior-posterior opening intothe internal cavity.
 3. The interbody implant of claim 2, wherein: theanterior-posterior opening is located on an anterior surface of theporous structure; and the porous structure further comprises a posteriorsurface including a plurality of ports.
 4. The interbody implant ofclaim 1, further comprising a porous support wall extending across theinternal cavity in a superior-inferior direction.
 5. The interbodyimplant of claim 4, wherein the support wall is located at amedial-lateral center of the interbody implant.
 6. The interbody implantof claim 1, wherein: the plurality of ports comprises a plurality ofhexa-lobular openings extending from an exterior of the porous structureto the internal cavity; and each of the plurality of ports comprises across-sectional area larger than a pore size of the porous structure. 7.The interbody implant of claim 1, wherein the porous structure comprisesa plurality of ligaments defining open spaces therebetween, theligaments forming a matrix of continuous channels having no dead ends,wherein the first cage is fabricated from a solid metal material and theporous structure is fabricated from the porous metal material and has aporosity mimicking that of natural bone.
 8. The interbody implant ofclaim 1, further comprising a second cage having anterior, medial,posterior and lateral segments contiguously connected to each other todefine an additional interior space, wherein the porous structure islocated within the additional interior space.
 9. The interbody implantof claim 8, wherein the first cage and the second cage are uncoupled ina superior-inferior direction.
 10. The interbody implant of claim 9,further comprising a threaded socket located on a medial or lateral sideof the interbody implant, the threaded socket having a superior portionlocated on the first cage and an inferior portion located on the secondcage.
 11. The interbody implant of claim 8, further comprising a wedgestructure located on an end of the interbody implant, wherein the wedgestructure comprises opposing tapered surfaces that form a thinnestportion of the interbody implant in a superior-inferior direction. 12.The interbody implant of claim 8, wherein: the first cage defines asuperior-most surface of the interbody implant flush with asuperior-most portion of the porous structure; and the second cagedefines an inferior-most surface of the interbody implant flush with aninferior-most portion of the porous structure.
 13. The interbody implantof claim 12, wherein the interbody implant defines an angle between thesuperior-most surface and the inferior-most surface, wherein the angleis in the range of approximately six degrees to approximately thirtydegrees.
 14. The interbody implant of claim 8, wherein: the anteriorsegments of the first and second cages are curved so that an anteriorside of the interbody implant is convex; the posterior segments of thefirst and second cages are curved so that a posterior side of theinterbody implant is concave; and a superior surface of the porousstructure is curved.
 15. The interbody implant of claim 14, wherein thefirst cage and the second cage are connected by a socket, wherein thesocket comprises a swivel coupling comprising: a superior wall having abore; an inferior wall having a bore; a first longitudinal surfaceconnecting the superior and inferior walls; and a second longitudinalsurface connecting the superior and inferior walls; wherein the firstand second longitudinal surfaces are disposed at an angle to each other.16. The interbody implant of claim 14, wherein the interbody implantdefines an insertion end and a coupling end and the first cage and thesecond cage are joined at the insertion end and the coupling end,wherein the first cage and the second cage are angled toward each otherat the insertion end of the interbody implant and the first cage and thesecond cage come together at a rounded tip at the insertion end.
 17. Theinterbody implant of claim 16, wherein the insertion end comprises apyramid and the coupling end includes a socket, wherein the insertionend is thicker than the coupling end.
 18. The interbody implant of claim14, further comprising a socket piece embedded into the porousstructure, wherein the socket piece is connected to the first cage andthe second cage.
 19. The interbody implant of claim 1, wherein asuperior-inferior stiffness of the interbody implant is defined by theporous structure.
 20. The interbody implant of claim 1, wherein thefirst cage comprises about 15% by volume of the interbody implant. 21.An intervertebral implant for lateral insertion, the intervertebralimplant comprising: a porous structure formed of a porous material, theporous structure shaped to define: an interior cavity; and a pluralityof longitudinal passages extending through the porous structure tointersect the internal cavity; a first cerclage cage horizontallysurrounding the porous structure; and a second cerclage cagehorizontally surrounding the porous structure uncoupled from the firstcerclage cage such that a longitudinal stiffness of the intervertebralimplant is defined by the porous structure.
 22. The intervertebralimplant of claim 21, wherein the porous structure comprises: a superiorpanel including a plurality of openings extending through the superiorpanel to partially define the plurality of longitudinal passages; aninferior panel including a plurality of openings extending through theinferior panel to partially define the plurality of longitudinalpassages; and a middle panel separating the superior panel and theinferior panel to define the interior cavity.
 23. The intervertebralimplant of claim 21, wherein the first cerclage cage and the secondcerclage cage include ramped end portions to provide the intervertebralimplant with a wedge-shaped insertion end.
 24. The intervertebralimplant of claim 21, wherein the first cerclage cage and the secondcerclage cage each include a partial coupling socket that together forma socket configured to receive an insertion tool.